1. Field of the Invention
This invention relates to lifting devices such as cranes, derricks, winches and hoists of the kind incorporating a pulley block equipped with a lifting hook or other like element.
2. Description of the Prior Art
It has been proposed to render the lifting element, e.g. hook, detachable from the pulley block while suspended by a separate cable to enable the hook alone to be lowered into position and secured to a load to be lifted before the pulley block itself is lowered. In this way the heavy pulley block, when it is lowered, is guided along the hook cable and the hook subsequently is reconnected with the block. This substantially avoids the difficulties and dangers which are otherwise encountered in adverse weather conditions or when the crane and/or the load is not stationary, as for example in transferring loads at sea from one vessel to another or to some fixed installation.